Related Content

"This is longstanding precedent at the DNC and has happened during multiple chair transitions," DNC spokeswoman Xochitl Hinojosa said. "The process was started before the election of the new chair. From the beginning, Tom has been adamant that we structure the DNC for future campaigns. Current and future DNC staff will be integral to that effort."

Leah Daughtry, an adviser to interim chair Donna Brazille and the chief executive officer of the 2016 Democratic National Convention, sent a letter asking every party staffer to submit letters of resignation dated April 15 immediately after Perez won the DNC chair race a month ago. NBC News first reported the request.

DNC staffers expected the request. The party had already been operating at reduced staffing levels, and had brought on some staffers on temporary contracts.

A Democrat familiar with the request called it normal in leadership transitions, and said the same thing has happened during previous installations of new party chairs. The move is also expected to allow Perez to make structural changes at the DNC that many party members consider overdue.

Already, a 30-person committee launched by Perez is interviewing potential new staffers as the party attempts to put the rifts caused by the 2016 primary contest between Hillary Clinton and Bernie Sanders behind it.

Also to be determined: The roles that new deputy chair Keith Ellison -- the Minnesota congressman who narrowly lost the party's chair race to Perez -- and other vice chairs will play.

The overhaul will be particularly welcome to progressives, who viewed the DNC under former chairwoman Debbie Wasserman Schultz as biased in favor of Clinton and against Sanders. Progressive activists, angered by Wasserman Schultz, called for wholesale changes at the DNC during the 2016 election.